Rudder



Oct. 12, 1943. LlvlNGsToN 2,331,706

RUDDER Filed Sept. 27. 1941 25 F2-Gf 'i214 e mi ff Oct. I2, 1943. J. LlvlNGs-roN RUDDER Filed Sept. 27, 1941 4 Sheets-Sheet 2 FIG. 4.

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ATTORNEYS,

Oct. 12, 1943. J, LIVINGSTON RUDDER Filed Sept. 27, 1941 4 Sheets-Sheet 5 INVENTOR Joy/v /v//vGs 70M ATTORNEYS.

0a. 12, 1943. J. LIVINGSTON 2,331,706

RUDDER Filed Sept. 27, 1941 l 4 sheets-sheet 4 72 7-- l n E 1 "m '65 "U |||H I i I ,W1 um 11H 1| 1| 1mm, 1 Mh l' f4 um Ehm;

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2,331,706 RUDDER f J ohn Livingston, Pelhamli/Kaner, N. Y. Application September 27, 1941,Serial No. 412,533

s claims. (o1. 114-162) This invention relates to a rudder and is concerned primarily with a ships rudder of the balanced type, though some features of the invention have a wider application.

Some of the advantages of the invention are of a functional nature, while others have to do with the construction of the rudder.

Among the operating advantages of the rudder, as compared withan ordinary streamline balanced rudderyfor example, are the following: improvement in propulsive efficiency; reduction in rudder torque, or force required to turn the rudder; limprovement in steering and maneuvering quality, resulting in a straighter course of the vessel; reduction in vibration.

The constructional advantages include: increased strength, reduced weight,v lower cost, more rapid production, and greater freedom from external causes of delay in production.

The invention will be described in detail with reference to two illustrative forms shown in the accompanying drawings.

Fig. 1 .is an oblique perspective View of the rudder, from a station point slightly above the top and forward of the leading edge of the rudder;

Fig. 2 is an angular perspective view of the rudder, from a station point in the median plane and slightly forward of the leading edge of the rudder; and

Fig. 3 is a front elevation of the rudder.

Figs. 4 to 7 and 8 illustrate ltwo ways in which the rudder can 'be cnnstructed':

Fig. 4 being a side elevation of the stern of a ship, showing the rudder in substantially vertical section along the line 4 4 of Fig. 3;

Figs. 5 and 6 being horizontal sections taken respectively on the lines 5 5 and 6 6 of Fig. 4;

Fig. 'l being a side elevation of a small portion of the rudder, showing a detail of the construction method; and

Fig. 8 being a condensed vertical sectional view of a rudder .of modified construction in accordance with my invention.

The rudder shown in Figs. 4 to 6 cf the drawings is a balanced rudder of the type sometimes called a iishtail rudder. It is composed of an upper part I, and a lower part 2, sometimes called herein the upper rudder body and the lower rudder body, respectively, which are joined together will be described, would be reversed for use with a left hand propeller. It is well known that the streams of water from the rdiiferentjparts of a screw vpropeller blade at different distances from the kpropeller axis are deflected in different directions, ythose propelled from the tipof the blade having a nearly fore and aft' direction, while those from near the hubjhave a'greater lateral inclination. The differentpartsofthe propeller stream therefore strike the forward edge of the rudder from 'different directions. The part of the propeller stream striking the upper rudder body near the top is directed a1- most vdead astern, while the part striking the upper" rudderibody near the bottomhas a de- -cided inclination to starboard. At the lower rudder body the conditions are just reversed,l the part of the propeller stream near the bottom being udirected almost `dead astern, while the part of the propeller streamV near the top of the lower rudder body has a decided inclination to port. l v

The leading surfacesoflthe rudder, by which I mean that part of the steering surfaces 'situated forward of the pivotal axis' vA-A, are shaped to meet the different parts of the propeller stream. with the least resistance to 'their flow. The leading surfaces 5 and 1 of the upper part of the rudder meet to form a leading edge 8 curving downward and outward from a point 9 in the longitudinal median plane of the rudder to a point lil o'lset :from the median plane toward the rising Aside of the propeller, which is `the port' sidein this case. The leading surfaces H and l2 of the lower part of the rudder meet to form a leading edge |i3' curving vupward and outward from a point 'I4 in the median plane .of

' the rudder to a point l5 offset from the median at the 'level of the propeller axis 3. l The rudder plane toward the downwardly moving. side of the propeller, which is the` starboard side in this case. In other words,-the leadingV surfaces of the upper rudder body have a warp to por-t, while the leading .surfaces of the lower'rudder body have a `warp to starboard; thus their proximate portions are offset from each other by the sum of their divergences from the median plane of the rudder.

An important feature of the present invention is the provision of a segregating web I6 joining and extending between these two relatively offset portions `of the upper and lower rudder bodies.

'It has been explained that thepart of the propeller stream striking the leading edge just below the propeller axis is correspondingly inclined to port. These two adjacent parts of the propeller stream therefore have crossing directions of Ilow, which would result in considerable turbulence if they were allowed to come into contact with each other. The web I6 prevents such contact and allows the two parts of the propeller stream just above and below the propeller axis to flow smoothly past eachother along their crossing paths. The turbulent condition, which would be created at the leading surfaces of the rudder if these two parts of the propeller stream were allowed to come into contact with each other, would cause serious operational disturbances, since theeddies so caused would ow along the whole length of the steering surfaces of the rudder, interfering with its steering action, reducing the propulsive eiciency, and causing vibration.

Aft of the pivotal axis A-A the two rudder bodies are shaped in conformance with the leading surfaces described: at the top of the upper rudder body I and at the bottom of the lower rudder body 2 the contour of the rudder is symmetrical, or nearly symmetrical, to the longitudinal median plane, while the bottom of the upper rudder body and the top of the lower rudder body flare divergently from the median plane. The trailing surfaces 20 and 2l of the upper rudder body meet to form a trailing edge 22 which curves downward and outward from a point 23 in the longitudinal median plane of the rudder to a point 24 offset from the median plane to the starboard. The trailing surfaces 25 and 26 of the lower rudder body meet to form a trailing edge 21 which curves upward and outward from a point 28 in the longitudinal median plane of the rudder to a point 29 offset to port from the median plane. These trailing surfaces are thus warped oppositely from the longitudinal median plane of the rudder and their proximate portions are offset from each other by the sum of their divergenees from the longitudinal median plane. A web I1 joins and extends between these relatively offset portions.

Tests of a rudder having the form described, in comparison with other balanced rudders of symmetrical and nearly symmetrical types, showed a number of operating advantages of my rudder. 'I'he propulsive efficiency was improved, due to lower resistance, elimination of eddies, and straightening of the propeller stream. The rudder torque was reduced, due to the special form and better balance of the rudder. The steering and maneuvering quality was improved, due to the better form and elimination of eddies, resulting in a straighter course of the vessel. Vibration of the rudder was reduced, due to the more uniform flow of the propeller stream past it.

Figs. 4 to 6 and 8 show two of the ways in which the rudder can be made, the construction shown in Fig. 8 having certain advantages which will be explained later. In accordance with Figs. 4 to 6 a rudder stock is first made by cutting a pipe or tube 30 of suitable diameter to a length slightly shorter than the height of the rudder, and welding castings to its two ends to provide means for pivotally mounting the rudder. The lower casting 3| comprises a pintle 32 upon which is fitted a brass bushing 33. When the rudder is stepped, the bushing 33 ts into a thrust bearing 34 in the shoe 35 of the stern frame. The upper casting 36 extends in the form of a shaft 31 up through the counter of the vessel,

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where it is journalled in bearings which do not appear in Fig. 4.

At spaced intervals along the tube 30 are welded diaphragm plates 43a, 4017, 40e, 49d, 40e, 40j and 43g; also diaphragm plates 4Ia, Mb, 4Ic, Md, 4le, 4If and 41g. Each of these plates has a different contour, depending upon the horizontal cross section of the rudder at its particular level. There are also a bottom plate 42, a top plate 43, and a shelf plate 44, all of considerably heavier stock than the diaphragm plates. The bottom plate 42 is welded to a flange 38 of the casting 3|, while the top plate 43 is welded to a flange 39 of the casting 3S. The shelf plate 44 is welded to the tube 3U at the level of the propeller axis. There are also shown two vertical diaphragms 45 and 46 between the top plate 43 and the horizontal diaphragm plate 40g, and between the latter and the horizontal diaphragm plate 40j. In addition, there are a number Vof brackets 41 welded to the top plate 43, the shelf plate 44, and the bottom plate 42. To the forward ends of the diaphragms 4in1-g, the top and bottom plates 43 and 42, and the shelf plate 44, are welded two pipes or tubes 48 and49, which are to constitute the leading edge of the rudder. The shape of these pipes can best be seen in Fig. 3, where they are indicated by the reference numbers 8 and I3, respectively.

When all the diaphragms, the top and bottom plates, the shelf plate, the brackets and the pipes 43 and 49, have been welded in place, the rudder framework is ready for the mounting of the side plates upon it. These may be preliminarily shaped substantially to the final form which they are to have in the rudder. For drawing them against the diaphragm plates I prefer to use the wedging system represented in Fig. 6. which shows a plan view of the diaphragm plate 40e. The diaphragm plate is originally formed with a series of lugs 50 distributed along its edges, each adapted to project through a slit 5l in the side plate 52 (see Fig. '1). Each lug 50 has a hole 53 to receive a pin 54 behind which can be driven a wedge 55 to force the side plate 52 against the profile of the diaphragm plate 40e. When the side plate is driven home, the lug 50 is welded to the side plate all around, completely lling the slit 5| and making a Water-tight seal; then the lug is cut off flush with the outer surface of the side plate. as shown at 50a. There may be one side plate 52 extending all the way from the trailing edge 22 to the leading edge pipe 48, in which case the side plate is plug-welded to the pipe 30 at 30a along their line of contact. The front edge of the side plate 52 is welded at 6| to the pipe 48. Alternatively, the plate 52 may be in two parts, one part extending from the trailing edge 22 to the line of tangency with the pipe 30 and the other extending forward to the pipe 48, leaving a narrow gap at 30a along the pipe 30 for a continuous Weld. The side plate 52 rests at its lower edge upon the shelf plate 44 and is welded thereto along the entire line of contact 62 (Fig. 5). The top plate 43 rests upon the upper edge of the side plate 52 and is welded thereto in the same way as the shelf plate. The other side plates are all brought into position and welded to the framework in the same way as the side plate 52. The side plates are welded to each other along the trailing edges 22 and 21.

It will be observed that the shelf plate 44 serves not only as a part of the framework upon which the side plates are mounted, but that it also has exposed portions constituting the segregating 1253er ,vos

'webs Fand "Ill an'dfcovers up the bottom of the fupper rudderbodyand thetop of thelower rudder body. The pipes #d6 and Ilidia-re o'f extralheavy stock vbecauseffof `the 'heavy Lduty they have to perform, positioned, :as they are, directly beliind the propeller -vlrere they must take Ethe pounding of Vthe -water and any -debriscarried against them by fthexpropeller stream. 'The shelf Iplate andthe 'top and bottom Lplates are also -'of r'extra heavy stock. According to technical classification, lthe tubular members 35i, 48 and 429 may '-be veither Etribes or pipes. `rInpraotice I Aherve used tubes '-for I'tne member '30 and pipes for the members 38 and 5B. AIn theelaims the itermpipe` is used iin the K stoel: extension '49 and fseoure fthe latter Vto the "tube ill). A key liiiilon the lface of the 'rudder stoel: extension T9 engages corresponding grooves 1in Ithe 'top of the tube fill and vring .Bef-ore `the rin-g TM is welded toliire top of tube "fd Ia 'bushing -lfi v'of brass or other suitable material is passed l lover thelend of the tube 7i) and-sli1'uni onto 'the saine at v`the lcorrect position to provide la bearing surface at the `ilevel of `the neck bearing T3. 'The neck bearing is secured 'to fa flange B2 tlre transom frame and is preferably provided with a bearing-sleeve 383 of lignum vitae. The top plate 'l2 has an aperture corresponding to the size of the tube Hl and is welded to the tube all around at lill and 65. The bottom end of the rudder stock is provided with journal means to be received in the step bearing and for this purpose I have shown a pintle casting 86 similar to the one shown in'Fig. 4. In this case the flange 33 is eliminated and the bottom plate 'H is welded all around to the pintle at 31. The tube 'lll is plug-welded to the pintle at 88. A brass bushing 89 covers the lower end of the pintle.

The construction just described has ther advantage over the first embodiment, that the upper shaft casting 36, 31 of the latter is eliminated and the procurement of parts thereby much simplified. Moreover, the possibility of slipping the brass bushing 8l over the upper end of the tube 'lil and shrinking it on eliminates considerable difficulty in providing the proper bearing surface for the rudder stock at the neck bearing.

The described constructions have a number of advantages over earlier rudder constructions. They are composed entirely of stock sheet and tube metal and one or two simple castings. This is always an advantage, but particularly so at a time like the present when production facilities are so heavily taxed that the customary forgings or heavy castings requiring machining will not be guaranteed for delivery at any specied time. In addition to this the cost is much reduced by the elimination of forgings, heavy castings, flanges, and riveting, as well as reduction in machining and labor. The weight of the rudder is also reduced, yet it has greater strength than rudders of heavier design.

I claim:

1. A balanced rudder to be mounted on a vertical pivot in the propeller stream, having steerdownwardly moving side of the propeller, anda 'segregating web 'joining and Vextending between the bottomportion fof said upper part and the top portion of said lower 'partof the rudder L'forward of the rudderpivot at approximately Athe level Aof the propeller axis. f

2. Abal'anoed rudder to be mounted on la vertical pivot inthe propeller stream, having "steering surfaces both fore and aft of its pivot, the steering sur-faces of the Vtwo sides of the upper part of the rudder above the axis 'of the propel- :ler sha-ft 'and forward lof the rudder pivot meeting at their forward'ends in a 'line running from a point at the top yof the rudder approxi-mately -in -the fore-and-aft plane through the rudder pivot to a point offset from said. plane 'toward the rising side of the propelli'ar :at the level 1o'f the propeller axis, the steering surfaces fof the "two `sides of the lower part :of the rudder `-below the propeller axis andfforward of the rudder `pivot meeting at their forward 'ends in a line running 'from a point at the bottom of the rudder 'approximately in the said fore and aft plane through the rudder pivot 'to 'a point offset from said plan'e toward the downwardly moving side o'f the propeller at the level of thepropeller axis, and 1a' web joining rvand extending lbetween 'the bottom portion of said 'upper part and thetop portion of said lower part of the rudder forward of the rudder pivot at approximately the level of the propeller axis.

3. A balanced rudder to be mounted on a vertical pivotvin the propeller stream, composed of upper and lower rudder bodies joined together at approximately the level of the propeller axis, the leading surfaces of said upper rudder body being warped so as to meet along a leading edge extending downward and outward to one side of the longitudinal median plane of the rudder, the leading surfaces of said lower rudder body being warped so as to meet along a leading edge extending upward and outward toward the other side of said median plane, the proximate portions of the leading surfaces `of said upper and lower rudder bodies being therefore relatively offset, and a segregating web joining and extending between said relatively offset portions of said leading surfaces.

4. In a, rudder construction, a rudder stock, a shelf plate fixed to said rudder stock at the level of the propeller axis and extending forward and aft of the rudder stock, two streamline rudder bodies extending, respectively upward .and downward from said Shelf plate and fixed thereto, the portion of the upper rudder body adjacent said shelf plate and forward of the rudder stock being directed toward the rising side of the propeller, while the portion of the lower rudder body adjacent said shelf plate and forward of the rudder stock is directed toward the downwardly moving side of the propeller, the forward edges of the upper and lower rudder bodies being laterally offset from each other to a substantial extent at the plane of the shelf plate and said shelf plate comprising a portion forming a segregating web between the relatively offset portions of said upper and lower rudder bodies forward of the rudder stock.

5. In a rudder construction, side plates forming a streamline rudder body, a rudder stock within said rudder body composed of a pipe having a pintle welded into its lower end and a shaft welded into its upper end, the diameter of said pipe being equal to the distance between said side plates in the transverse vertical plane through the axis of the rudder stock, horizontal diaphragm plates welded-at spaced intervals to said pipe and having outlines conforming to the contours of the rudder body at their respective levels, said side plates being welded to said pipe and to said diaphragm plates and being held thereby to the shaped peripheries of said diaphragm plates.

6. In a rudder construction, side plates forming a streamline rudder body in two parts respectively above and below the propeller axis, the horizontal contour of said parts at the top and bottom of the rudder respectively, being symmetrical to a common fore-and-aft vertical plane, said upper and lower parts being oppositely twisted and oppositely divergent from said common plane at the level of the propeller axis, a rudder stock within said rudder body composed of a pipe having a pintle welded into its lower end and a shaft welded into its upper end, the diameter of said pipe being equal to the distance between said side plates and the transverse vertical plane through the axis of the rudder stock, a shelf plate welded to said pipe at the level of the propeller axis and welded to the bottom and top respectively of the side plates forming the upper and lower parts of the rudder body, said shelf plate covering completely the bottom and top, respectively, of said upper and lower parts of the rudder body and forming a web joining said parts, horizontal diaphragm plates welded at spaced intervals to said pipe above and below said shelf plate and having outlines conforming to the contours of the rudder body at their respective levels, said side plates being welded to said pipe and to said diaphragm plates and being held thereby to the shaped peripheries of said diaphragm plates.

7. A rudder construction as described in claim 6, wherein said rudder body is of the balanced type and the contours of the upper and lower parts thereof at the level of said shelf plate diverge oppositely from said common plane both fore and aft of the rudder stock, said shelf plate having web-like parts extending between said divergent parts of the rudder body and forming guide surfaces both fore and aft of the rudder stock.

8. In a rudder adapted to be pivotally mounted in a neck bearing on the transom and a step bearing on the shoe of the stern frame of a ship, a rudder stock comprising a pipe of a length greater than the distance between said two bearings, said pipe having journal means at its lower end, to be received in the step bearing and journal means near its upper end to be received in said neck bearing, and a rudder body comprising a plurality of horizontal prole plates welded at spaced intervals to said pipe, and side plates welded to the peripheries of said horizontal plates to form a hollow streamline rudder body.

J OI-IN LIVINGSTON. 

